This is a cute project! Great idea and a cute logo to go with it.
What size chart do you have now and how big does it have to be? (Maybe you can just accept every square to be 2 stitches and 2 rows or 3 stitches and 3 rows and just work from the chart as it is).
You can always draw the chart by hand with a big print of the logo on paper and calculating how wide of a grid you have to sketch over it. But if you have a sufficient grid already it would be easier to work off of that.
The color I would match in the store with something with the exact logo colors to hold onto the yarn. Online pictures will definitely not do for an exact match.
I do not remember ever seeing color numbers of general type on yarn or yarn sites. Maybe somebody else will know something about that, though.
Continental Knitter with passion, pretty busy and always onto something new.
I have been away from the forum for a bit, but I am still around!